Unsaturated polyester resins have been used in varied applications, such as in polyester vehicle body filler systems and glass reinforced polyester vehicle body filler systems used in the automotive body repair field. These body fillers are used in the automotive repair aftermarket industry under a wide range of ambient air temperatures based on seasonal variations and in different regions around the world. In countries that lie near the Equator, temperatures often exceed 35 degrees Celsius. Furthermore, the use of air conditioning in automotive repair shops is not widespread even in temperate climates during summer months. Similarly, in colder climates, even when heaters are used, temperatures rarely reach 20 degrees Celsius owing to the need for ventilation. At high ambient temperatures, relative to the optimized cure temperature of 20 degrees Celsius, vehicle body repair formulations currently used by the industry tend to cure too quickly; and usage at below the optimal cure temperature, vehicle body repair formulations currently used by the industry tend to cure too slowly. Such extreme ambient temperatures, and the negative effects they have on cure time, lead to defects such as tacky surface, poor featheredging, poor adhesion, blistering, lifting and pin-holing. Adjusting the amount of catalyst present in the formulation is a method currently used in the industry to try to mitigate this problem. However, in practice it is extremely difficult to accurately adjust the amount of catalyst on-site because most vehicle body repair shops do not have scales and technicians cannot accurately measure out the proper amount of catalyst or homogenously mix the same into a mastic. Another method currently used in the industry is the use of heating or cooling equipment to mitigate the effect extreme ambient temperatures has on cure time of vehicle body repair formulations. However, many automotive repair shops do not have adequate equipment. Infrared lamps, for example, can be quite expensive and require a skilled operator to avoid blistering and lifting on the vehicle part being repaired. Additionally, blower fans tend to impart particulate into the finish and create skinning of the curing formulation.
Thus, there exists a need for a polyester resin formulation with additive that provides control of work time and cure time at extreme ambient temperatures. There further exists a need for a formulation that cures within an appropriate amount of time via exposure to ambient air alone, thus dispensing without the need for additional equipment to achieve an appropriate cure time.